Jailed Russian opposition politician Alexei Navalny is dead, the prison service of the Yamalo-Nenets region where he had been serving his sentence, said on Friday.

Mr Navalny, an outspoken critic of Russian President Vladimir Putin, has been in Russian jail since 2021 on charges that are widely viewed as politically motivated.

In August, he was found guilty of founding and funding an extremist organisation, which he denies, and was given an extra 19 years to his existing sentence.

He had already been sentenced to nine years for parole violations, fraud and contempt of court.

Kremlin spokesman Dmitry Peskov said Russian's penitentiary service was making all checks regarding Navalny's death but had no information about the matter.

Kira Yarmysh, Navalny's spokesperson, said that they don't have any confirmation of his death yet.

In a post on X (formerly Twitter), she wrote: The Federal Penitentiary Service in the Yamalo-Nenets District is disseminating news about the death of Alexei Navalny in IK-3. We dont have any confirmation of this yet.

Navalnys lawyer is now flying to Siberia and his team will report more information as they have it, she added. (BBC)

PHOTO: This handout picture provided by the Babushkinsky district court on February 12, 2021, shows Russian opposition leader Alexei Navalny, charged with defaming a World War II veteran, standing inside a glass cell during a court hearing in Moscow. Handout / Moscows Babushkinsky district court press service / AFP